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zzr overheating

Discussion in 'Technical and Troubleshooting Torque' started by flexorcist, Sep 2, 2006.

  1. recently my zzr250 has been lasting about 30 minutes in traffic before getting really hot when i come to a standstill.... the temp gauge still hasn't gotten all the way to hot but it's boiled twice. could it be that my fan is stuffed?? i've cleared out the radiator, but i live in a dirt st so it still gets a bit messy. temp is fine once i get going but i can feel it on my legs when it gets too hot, regardless of what the gauge says. it was all good before i dropped it :)... however i didnt bust the radiator or anything, i think i might have doen something when i took the frotn fairings off. any suggestions to keep it a bit cooler??

  2. i would check that the thermo fan is working.
    when it gets hot you should be able to hear the fan working.
    if thats working, i suggest you get your radiator flushed/cleaned.
    if it only started since you removed fairings, check that you havent undone the thermofan switch or relay which you will find by following the wiring back from the fan.
  3. thanks will do... it's kinda a biatch to get to :grin:
  4. is there a fuse somewhere as well do you know??
  5. there would certainly be a fuse, not sure where the fusebox is on a zzr.
    yes a fully faired bike does make working on it suck.
    however i would be going to the trouble of investigating it because everytime you overheat you are damaging your motor.

    good luck
  6. fuses on the zzr can be located inside the right side cover inside the junction box . There should be some spare fuses in the junction box. The main fuse is located on the starter relay next to the junction box. The junction box lists correct capacity fuses to use.

    Also, have you checked the coolant level?

  7. :LOL:
    yes, do that prior to taking stuff appart....silly me :oops:
  8. Does it actually overheat, or puke coolant out of the overflow? You did say it boiled, so I assume a proper overheat.
    To be able to sit in traffic for a half hour before overheating would indicate the fan is coming on, I'd imagine 10 mins of traffic with no fan would overheat any liquid cooled motorbike.
    As Joel has said, take the fairings off and have a good look.
    I would take fairings off, start and run bike whilst watching it warm up. Leave it running. The fan should kick on when the gauge reaches about half way, if it doesn't let it keep on idling for a bit, and see how she goes.
    When it's nice and hot, check the temperature switch, use a test lamp, leave the wires plugged into the switch, ignition on, earth the alligator clip to teh frame or engine, and backprobe the wires on teh switch. The test lamp should light at both wires. If it doesn't there's your problem. If it does, move to next step.
    Grab a piece of wire long enough to go to the battery, strip both ends. attach wire to positive batery terminal, and attach other end of wire to the positive side or the fan wiring. Fan should spin. If not, there's your problem. If fan spins when bridged this way, leave engine and fan running and check to see if the fan will pull the temperature back down whilst running continuously. If not, you have a cooling system problem, possibly head gasket.
    Let teh bike cool down and take radiator cap off. It should be full to teh brim. If not, possible radiator cap problem, or coolant loss in engine.
    Start engine. As soon as you start engine, (it must be cold) take radiator cap off. If the system is pressurised when the cooling system is cold and engine is running, head gasket leak. Leave cap off and let it come up to temperature. The coolant will start flowing out of the radiator neck when the thermostat opens. This coolant should be clear and no froth or bubbles. Froth or bubbles indicates a possible head gasket failure. Shut engine down once you establish coolant system is O.K or not. Check your oil, it should not be milky. If it looks like dark coffee or looks thick, head gasket failure.
    If you suspect a head gasket or cooling system problem, take it to a radiator shop. They have kits which can easily and quickly check for exhaust gases in the cooling system, and it saves a lot of guessing.
    The othee problem could just be a tired radiator. A chemical cooling system cleaner you can buy at spare parts stores will help, and may solve it, or may not. Follow instructions on the container to the letter.
    If the bike takes ages to warm up, and overheats in traffic, someone could also have removed thermostat.

    Regards, Andrew.
  9. thanks to everyone for your very very detailed replies!!! it's def not head gasket coz oil is fine bike runs fine etc etc... pretty sure it's just a combo of the fan and a dirty old radiator.... as tempting as it is i'm gonna keep a promise to myself not to fix anything myself... (if you saw the amount of half finished project cars i have you'd understand why i bought a bike) :grin: but yeah.... all your info helped heaps and at least i know exactly what's causing the problems! i think i want an air cooled bike next time :p
  10. Well if you leave it too long you might not get that choice; air-cooled bikes are getting thin on the ground these days :LOL:

    Seriously, the cooling systems of modern bikes are over-engineered to blazes; if you make sure the radiator is clean, running coolant and not just water, and the thermo fan is kicking in when it should, you should have nothing to worry about.
  11. I had same type of problem with my zzr after it fell over. Mine actually broke the radiator neck and had to be welded, but the over heat problem was after the fix. Typhoon's post was excellent (wish i had been on Netrider when i had my problems). it took us a while to get to the cause of my problem. Thermostat was replaced (was not the problem but was the first thing tried). You can get a testing fluid that does a colour change for exhaust gases detected in your coolant. BUT the main reason i am responding to your post - don't overlook the obvious - i had exactly the symptoms you have and after checking out that everything else worked as it should - we replaced the radiator cap and i have not had a problem since.
  12. it ended up being a dodgy temp switch that was the culprit... i fixed it like 6 weeks ago and the fan ain't workin again. is there anything in particular that likes to F** temp switches??
  13. All I can think of is excess current draw. Maybe wire up a relay to handle the high current when you put a new switch in. Or change switch brands?

    Regards, Andrew.
  14. possibly a voltage drop due to crappy connections somewhere between fan and power source, trace the wires back from the fan, through the temp sender, to the switch and then to the fuse box.
    a voltage drop causes what andrew describes above, because more current is required to drive the fan as power(watts)=volts x amps therefore to generate the same power with a crappy connection more amps are drawn.

    thats what i'd do...
  15. do me a favour.... dumb it down a notch :grin:

    i can do stuff when shown, not when told lol
  16. Give it a kick, or a hit with a hammer.

    If that didn't work, take it back to whoever fixed it for you the last time (you said you wouldn't do it yourself) and have them fix it properly. Must be under warranty. Fit for use, sale of faulty products, the law, I don't know, but it should last more than 6 weeks.
  17. my bike only ever overheated because the rider was so hot. It doesnt sound quite like your bike has the same issue, but its worth looking into.
  18. nah i fixed it myself last time... bit of speakerwire from the battery to the fan to see if that was working.

    and as for you :-----

    after 45 mins on my bike atm i got the hottest nuts around!! so could be the same th thang thang.